\begin{table}%t1 [!h]
\caption{\label{mfrac}Relative abundances $\left[\xi\right]=n_{\xi}/n_{b}$ of the elements
at the end of Big Bang nucleosynthesis for the SBBN and for two nonstandard BBN scenarios.}
%%\centering

\par
\small
\begin{tabular}{cccc}
\hline
\hline 
 & SBBN & \multicolumn{2}{c}{NSBBN}\\
 &  & $\left(f_{\rm v}=0.8;~ R=10\right)$ & $\left(f_{\rm v}=10^{-5};~ R=1000\right)$\\
\hline
$\left[{\rm H}\right]$ & $0.889$ & $0.889$ & $0.888$\\
$\left[{\rm D}\right]$ & $2.092\times10^{-5}$ & $2.45\times10^{-5}$ & $2.13\times10^{-5}$\\
$\left[{\rm He}\right]$ & $0.111$ & $0.111$ & $0.112$\\
$\left[{\rm Li}\right]$ & $1.77\times10^{-9}$ & $1.97\times10^{-9}$ & $2.30\times10^{-9}$\\
$\left[{\rm C}\right]$ & $2.51\times10^{-15}$ & $4.00\times10^{-15}$ & $8.45\times10^{-14}$\\
$\left[{\rm N}\right]$ & $2.32\times10^{-16}$ & $2.46\times10^{-16}$ & $3.44\times10^{-14}$\\
$\left[{\rm O}\right]$ & $3.22\times10^{-19}$ & $3.37\times10^{-19}$ & $8.20\times10^{-17}$\\
$\left[{\rm F}\right]$ & $3.28\times10^{-27}$ & $3.61\times10^{-27}$ & $1.63\times10^{-24}$\\
\hline
\end{tabular}
\end{table}